A combined peritumoral and intratumoral signature of HER2-E on pretreatment MRI was found to be significantly associated with pCR, consistent with the HER2-E subgroup’s superior response to HER2-targeted therapy compared with other HER2+ breast cancers.4 This association was supported in 2 independent validation cohorts from different institutions: one with high heterogeneity (PRC1: mixed magnetic strengths and scanner manufacturers, multiple treatment regimens, variability in voxel size) and the other with homogeneous treatment and MRI acquisition protocols. The gene discussed is ERBB2; the disease is breast carcinoma.